package com.jhws.util.security;




import com.jhws.util.LogHelper;

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {

	private static String byteArrayToHexString(byte b[]) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++)
			resultSb.append(byteToHexString(b[i]));

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n += 256;
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String MD5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = new String(origin);
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname))
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes()));
			else
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes(charsetname)));
		} catch (Exception exception) {
		}
		return resultString;
	}

	private static final String hexDigits[] = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };


	/**
	 * MD5加密
	 * @param str
	 * @return
	 */
	public static String md5(String str) {
		String result = null;
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(str.getBytes("UTF-8"));
			result = new BigInteger(1, md.digest()).toString(16);  //md5 32bit
		} catch (NoSuchAlgorithmException e) {
			LogHelper.e("MD5加密失败：" + e.toString());
		} catch (UnsupportedEncodingException e) {
			LogHelper.e("MD5加密失败：" + e.toString());
			e.printStackTrace();
		}
		return result;
	}

}
